1. Field of the Invention
The present invention relates to an image forming apparatus. More particularly, the present invention relates to an image forming apparatus having a structure for improving an assembly of the apparatus and a noise characteristic of a control signal.
2. Description of the Related Art
In general, an image forming apparatus is an apparatus that receives image signals and transfers images on a document. In addition, an image forming apparatus having an image scan function is an apparatus that reads an image recorded on a document, and converts the image into digital image information so that the image can be displayed on another paper or display device, such as a facsimile or a scanner.
The image forming apparatus having the image scan function typically includes a conveying unit that induces the document, on which the image is recorded, along a predetermined path into the image forming apparatus, and then discharges the document out of the image forming apparatus along a predetermined path. The conveying unit includes various kinds of rollers and a driving unit, such as a motor and a clutch, for driving the rollers.
In addition, the image forming apparatus typically includes a control unit for controlling operations of the conveying unit. In the conventional image forming apparatus having the image scan function, the control unit is constructed with a printed circuit board (PCB) having a microcomputer. For example, the conveying unit and scan unit that reads the image, are controlled using one PCB, such that the read image is converted into the digital image information. As described above, in the control unit comprising one PCB, wires for connecting the conveying unit and the scan unit or other elements, are concentrated on one PCB, thus it is not easy to order the wires and ensure a space on the PCB for connecting the wires. Consequently, the assembly of the image forming apparatus is degraded and excessively complicated.
Also, since sensors for detecting the position of the document on the conveying path are typically disposed some distance from the PCB, a number of long wires corresponding to the separation distance are used. Thus, the wires may protrude into the conveying path of the document, and may interrupt the conveying operation of the document.
In addition, signals of 3.3V˜5V are generally transmitted between the sensors and the PCB, however, the signal characteristics of the low voltage signal is degraded when the length of the wire becomes longer. Thus, noise may be generated due to the long wires between the sensors and the PCB.
A 24V signal that has a relatively higher voltage than the signal on the sensor connection wires is applied to the wire connecting the driving unit, such as the motor and the clutch, for driving the conveying rollers to the PCB. However, as described above, it is not easy to ensure the space for arranging the wires, thus the wire on which the 24V signal flows, may be adjacent to the sensor connection wires, on which the low voltage signals flow, and accordingly, a noise signal may be generated on the sensor connection wires by the high voltage signal.
Accordingly, a need exists for a system and method to reduce the number of wires that directly connect to the main circuit board, shorten wires between the circuit board and the sensors, and minimize noise signals.